Windshield wiper assemblies for motor vehicles basically include a drive shaft mounted on the vehicle body, below the windshield, and a drive arm mounted on the drive shaft for rotation therewith. The windshield wiper assembly also includes a wiper arm that is hingedly mounted to the drive arm and that carries a wiper blade adapted to be in contact with the windshield. The drive arm and the wiper arm are spring loaded such that the wiper arm and thus the wiper blade are urged into contact with the windshield. Typically, a helical spring extends between the drive arm and the wiper arm with the hinge connecting the drive arm and the wiper arm being located between the attachment points of the helical spring thereto. The drive shaft when actuated imparts a back-and-forth movement to the drive arm and thus to the wiper arm thereby causing the wiper blade to clear the windshield of rain, snow, and the like. Such an arrangement is also used for the wiper assemblies of rear windows of certain vehicles, such as hatchbacks, vans and SUVs.
Therefore, windshield wiper assemblies on vehicles are biased towards the windshield so that the wiper blade exerts a certain pressure against the windshield. Generally the wiper arm does not sit very high off the windshield and the helical tension spring that is stretched between the drive arm and the wiper arm does not have sufficient space to exert a long moment arm thus creating weak pressure on the wiper blade compared to the force exerted by the spring since it is working in tension with a short moment arm. Nevertheless, the spring must be extremely strong so as to create a sufficiently strong torque to generate a good pressure on the wiper blade so that in turn the blade gives a satisfactory wiping action against the windshield. However, wiper assemblies do not always maintain sufficient contact of the wiper blade against the windshield being wiped to keep the latter clean.
Moreover, as generally encountered at high vehicle speeds or when vehicle is facing strong winds, wind lift on the wiper arm and blade counteracts at least some of the force exerted by the spring thereby reducing the wiping action of the wiper blade in an unsatisfactory manner.
Accordingly, vehicle aftermarket products have been developed for increasing the wiping pressure of the wiper blade on the windshield. Such products are typically fitted onto the wiper assembly to increase the spring force acting on the wiper arm such as to provide better contact between the wiper blade and windshield being wiped.
There thus exist different types of devices that can be mounted onto windshield wiper assemblies so as to at least partly oppose a lifting effect of the wiper arm from the windshield when the assembly is in operation. Examples of such devices are disclosed, for example, in U.S. Pat. Nos. 2,782,450 (issued on Feb. 26, 1957 to Nesson); 2,885,710 (issued on May 12, 1959 to Brasty); 5,320,333 (issued on Jun. 14, 1994 to Koch); 6,804,855 B2 (issued on Oct. 19, 2004 to Lebel); and 6,931,691 B1 (issued on Aug. 23, 2005 to Ward); as well as in U.S. Patent Application Publication No. 2008/0155777 A1 in the name of Stull.
Though these devices allow for the wiper blade of a windshield wiper assembly to be in contact with the windshield of the vehicle, they may not fit on all existing types of windshield wiper assemblies and, more particularly, on the drive arm and wiper arm thereof. Indeed, there are multiple windshield wiper assembly models that are of different dimensions, whereby various sizes and configurations of these aftermarket devices may be required to properly fit these different wiper assemblies. For instance, the spring device of U.S. Pat. No. 5,320,333 has been manufactured in four different sizes so that the hook-like end portions thereof can be appropriately mounted to the drive arm and wiper arm of various models of windshield wiper assemblies.
There is thus still a need for a device for windshield wiper assemblies, which can be engaged onto many windshield wiper assembly models, i.e. which are of different sizes and/or shapes, and which increases the pressure of the wiper blade onto the windshield for providing a better contact between the wiper blade and the surface being wiped.